1. Field of the Invention
This invention relates to a tool for removing a chisel, in particular from a chisel holder, having a base element which receives an actuating member, wherein the actuating member has an expeller mandrel, and the actuating member is adjustable.
2. Discussion of Related Art
Similar tools are employed, for example, in connection with road milling machinery, recyclers, surface miners, and the like. They are used for removing chisels, in particular shank chisels, such as round shank chisels. In this case, the chisels are clampingly held in chisel receivers. Customarily, the chisel receivers are designed as through-bores. The chisel holders themselves are fastened to the surface of a milling roller tube, in particular welded to it, or are interchangeably fixed in base supports, which also are welded to the surface of a milling roller tube. Tools are known for making the removal of the chisels easier, such as are described in German Patent Reference DE 296 23 508 U1.
This tool has two lever arms, which are connected with each other by a joint. Here, one of the arms constitutes the expeller mandrel, and the other lever constitutes a handle element. The expeller mandrel can be inserted with its free end into the chisel receiver so that its end contacts the chisel shank of the chisel to be expelled.
The tool can be placed with the second lever against a support shoulder on the milling roller tube. Then, the chisel can be pushed out of the chisel receiver by a lever displacement. Finally, the expeller mandrel is threaded out of the chisel receiver. In the restricted assembly space, the manipulation of the double lever is difficult and is time-consuming. Further, the tool requires a support shoulder on the milling roller, which is not always available.
Removal tools are also known, which can be placed with draw-off claws against the chisel head of the chisel. In this case, a circumferential groove is required in the chisel head, into which the draw-off claws enter. It is not possible to perform a removal of the chisels, if the chisel heads are worn to such a large extent that the groove is no longer sufficiently available. Also, chisels with broken-off chisel heads cannot be removed. Such tools are known from German Patent References DE 43 23 699 C2, DE 32 23 761 A1, and DE 84 03 441 U1 and U.S. Pat. No. 6,526,641 B1.
A further tool is described in German Patent Reference DE 30 26 930 A 1. This tool has a support arm, which can be fixed in place against the chisel holder. A pivot lever, which has a handle, is coupled with the support arm. The chisel holder has a linearly displaceable plunger. For removing the chisel, a pivot arm facing away from the handle is placed against the plunger. As a result of displacing the handle, the plunger can be displaced and the chisel can be pushed out of the chisel receiver by it. The plunger, which is structurally connected with the chisel holder, constitutes an additional part and assembly cost. Further, it requires an increase in the structural space in the chisel holder, which is not always acceptable in connection with modern precision milling machines.
Also, this type of construction requires the fixation of the chisel in a blind hole-like chisel receiver which can become soiled during operation, which leads to a loss of the system.